1. Field of the Invention
The present invention relates to a structured catalyst for reforming of gasoline and a method of preparing the same, more particularly to a structured catalyst for reforming of gasoline for fuel-cell powered vehicles prepared by wash-coating the transition metal based reforming catalyst on the surface of the ceramic honeycomb support wash-coated with sub-micron sized alumina or its precursor to sufficiently increase the effective surface area and the performance of the catalyst and a method of preparing the same.
2. Description of Related Art
Researches on fuel processors for fuel-cell powered vehicles are currently on the active progress worldwide. There are many challenges, such as lightweightness, compactness, durability, dynamic load, thermal balance control, CO concentration control and startup time, in developing a fuel processor for a fuel-cell powered vehicle. Especially, a compact system is essential to develop an on-board gasoline fuel processor.
A gasoline fuel processor mounted on a fuel-cell powered vehicle comprises a desulfurizer, an autothermal reformer(ATR), a water gas shift(WGS) reactor, a preferential partial oxidation(PROX) reactor, system equipments and controllers. For commercialization of a fuel processor, development of a structured catalyst capable of maintaining catalytic activity is necessary along with development of a catalyst having superior performance for each reaction.
Structured catalysts are used in various fields including vehicles exhaust gas purifying catalysts, as environmental regulations on the air become more strict. Especially, they are used to convert nitrogen oxides generated in combustion facilities, such as power plants, incinerators and engines of ships, by selective catalytic reduction (SCR), to adsorb a variety of noxious gases generated during semiconductor-manufacturing processes and to remove a variety of volatile organic compounds (VOCs).
As a support of structured catalyst, the monolithic type modules are most favored. For example, they are easily found in the reactors for removing such impurities as hydrocarbons, NOx and VOCs from exhaust gases and the honeycomb type reactors for treating vehicle exhaust gases. The honeycomb type reactors are extrusion-molded to have honeycomb-shaped cross-sectional paths. They are used widely because of relatively large surface area per unit volume. A support with large surface area and/or a catalyst are impregnated on the basic monolithic type module having regular paths parallel to the direction of gas flow by wash-coating method.
Since the introduction in the early 1970s the honeycomb type reactors have been widely used. U.S. Pat. Nos. 4,072,471, 5,547,641 and 5,145,825 disclose honeycomb reactors, reaction processes thereof, optimization of catalytic materials and preparing methods thereof.
However, most of the preceding researches focus on honeycomb reactors for removing such impurities as hydrocarbons, NOx and VOCs from vehicle exhaust gases, and there have been few researches on gasoline reforming structured catalysts for fuel-cell powered vehicles.
In recent years, researches on processing reactions for fuel-cell powered vehicles have been reported in Korean Pat. Application No. 2002-21236, U.S. Pat. No. 6,183,703 and European Pat. No. 977,293. They are about heat supply method suitable for fuel reaction equipments, catalytic system array for each reaction process (POX, WGS, de-Sulfur, PROX and so forth), fuel injection method and fuel injection line system and catalyst filling layer.
Most of the preceding researches are performed using powder type or pellet type catalysts, which increases reactor volume and pressure when applied to the kW level. Therefore, a structured catalyst having good thermal stability and mechanical strength while capable of reducing reactor pressure is highly needed.